Flaps or slats maximum extended altitude?

Flaps or slats maximum extended altitude?

• A. 15,000' MSL
• B. 20,000' MSL
• C. 25,000' MSL
• D. 30,000' MSL

Answer: (B)

High-lift devices like flaps and slats are designed to work safely within a defined aerodynamic and structural envelope. When they’re extended, they add drag and alter the loads the wing and flap mechanisms must withstand. As you climb and the air gets thinner, the margin between the loads generated with the devices extended and what the structure can safely handle shrinks. To keep handling, stability, and the mechanism within approved limits, the aircraft is certified to have flaps or slats extended only up to a certain altitude. For this airplane, that limit is about 20,000 feet, so the maximum extended altitude is 20,000 ft MSL. Above that, extending them could exceed design limits and affect controllability, which is why you’d retract them.

High-lift devices like flaps and slats are designed to work safely within a defined aerodynamic and structural envelope. When they’re extended, they add drag and alter the loads the wing and flap mechanisms must withstand. As you climb and the air gets thinner, the margin between the loads generated with the devices extended and what the structure can safely handle shrinks. To keep handling, stability, and the mechanism within approved limits, the aircraft is certified to have flaps or slats extended only up to a certain altitude. For this airplane, that limit is about 20,000 feet, so the maximum extended altitude is 20,000 ft MSL. Above that, extending them could exceed design limits and affect controllability, which is why you’d retract them.